1. Field of the Invention
The present invention generally relates to a button sewing machine for sewing a sew-through button or mannish button on a piece of fabric such as, for example, a garment or apparel including a coat, suit, trousers and so on.
More particularly, the present invention relates to the button sewing machine having a dual function of making a looped thread between the sew-through button and the piece of fabric to attach the sew-through button to the piece fabric and then making a spinned cluster of thread (known as a wrapping neck) wound around a portion of the looped thread between the sew-through button and the piece of fabric to keep the sew-through button spaced a distance apart from the piece of fabric, and also to a button sewing machine capable of making the spinned cluster of thread around that portion of the looped thread between the sew-through button and the piece of fabric to keep the sew-through button spaced a distance apart from the piece of fabric.
2. Description of the Prior Art
As is well known to those skilled in the art, the sew-through button is known as a button of a type having at least two sew-through holes through which a needle is repeatedly pierced to pass thread therethrough to sew the button on a piece of fabric. When it comes to the fastening of the sew-through button on the piece of fabric, a looped thread is formed between the sew-through button and the piece of fabric, extending from, for example, one of the sew-through holes in the button to the piece of fabric and then through the other of the sew-through holes in the same button after having turned backwards at the opposite side of the piece of fabric and again extending from such other of the sew-through holes over a bridge portion between the two sew-through holes into such one of the sew-through holes. The looped thread so formed to sew the button on the piece of fabric generally consists of a number of turns of thread.
It is also well known to those skilled in the art that turns of thread forming the looped thread and located in a space between the sew-through button and the piece of fabric are bundled together to provide a spinned cluster of thread to keep the sew-through button in a generally floated fashion relative to the piece of fabric, that is, to keep the sew-through button spaced a distance apart from the piece of fabric, which distance corresponds generally to the thickness of the opposite piece of fabric in which a button hole is formed, so that the button on one piece of fabric can easily and smoothly be passed through the button hole in the opposite piece of fabric, it being noted that one piece of fabric and the opposite piece of fabric may be different portions of the same garment or clothing.
In order to sew the sew-through button on the piece of fabric firmly and in the generally floated fashion, it is generally necessary to perform a job (hereinafter referred to as a button sewing job) of sewing the sew-through button on the piece of fabric to form the looped thread therebetween and a job (hereinafter referred to as a bundling job) of forming the spinned cluster of thread around the turns of thread forming the looped thread. The thread forming the looped thread during the performance of the button sewing job and the thread forming the spinned cluster of thread during the performance of the bundling job may be continuous or separate from each other.
Although the bundling job to form the spinned cluster of thread for bundling the turns of thread between the sew-through button and the piece of fabric together may not be always essential, the performance of the bundling job, that is, the formation of the spinned cluster of thread, subsequent to the button sewing job is effective not only to permit the sew-through button to be firmly secured to the piece of fabric, but also to permit the sew-through button to be kept in the generally floated fashion relative to the piece of fabric. To keep the sew-through button secured to the piece of fabric, in the generally floated fashion relative to the piece of fabric, is particularly advantageous in that the button so sewed on the piece of fabric can be easily and smoothly engaged through the button hole defined in the opposite piece of fabric.
According to the prior art, the button sewing job and the bundling job are performed either by the use of separate sewing machines each exclusively designed for the respective job, or by the use of a single sewing machine which, although designed for the button sewing operation, requires an accessory or attachment, specially designed for the bundling operation, to be fitted to a needle plate or slide plate of the sewing machine.
Where the two sewing machines are employed for the button sewing and bundling operations, respectively, not only does an apparel manufacturer tend to be constrained by reason of economy since these two sewing machines employ a number of similar component parts, but the apparel manufacturer is also required to prepare a relatively large space for installation of the sewing machines. Moreover, the use of the separate sewing machines for the streamlined accomplishment of the button sewing and bundling jobs requires attendant workers to perform separate placement jobs for the setting of the piece of fabric on the respective sewing machine in readiness for the job to be performed. This renders the work efficiency lowered.
In the environment in which the single sewing machine which requires the use of the specially designed accessory or attachment as hereinabove described is employed, an attendant worker is required to undergo a sequence of removing the piece of fabric, on which the sew-through button has been sewed, from the sewing machine, then setting the specially designed attachment on the sewing machine and placing the once-removed piece of fabric again on the sewing machine in readiness for the bundling operation. Accordingly, as compared with the environment in which the two sewing machines are employed, the use of the single sewing machine constitutes a cause of a considerable reduction in work efficiency.
As far as the button sewing operation hitherto performed in the art is concerned, where the position from which the bundling operation is started relative to the piece of fabric is to be changed in a direction along the lengthwise direction of the thread, a mechanical method is employed in which a plurality of different types of cam members must be provided so that the start position at which the bundling operation is initiated can be changed by the replacement of one of the cam members with a different one of the cam members.
If the number of stitches to be performed to secure the sew-through button on the piece of fabric is properly chosen depending on the length, diameter and/or material of sewing thread, a high quality button fitting in which the sew-through button is sewed firmly on the piece of fabric in the generally floated fashion can be accomplished in a manner similar to that accomplished by hand. However, with the prior art button sewing machine, even a mechanical method is employed for the selection of the number of stitches to be performed, in such a way as to replace one cam member with another cam member.
The above described prior art methods require a complicated and time-consuming replacement job to change the type of cam member through a partial dismantling of the sewing machine each time the starting position at which the bundling operation is initiated and/or the number of stitches for the bundling operation are altered, thereby compounding a reduction in work efficiency.
An example of the prior art button sewing machine designed to perform the bundling operation is fragmentarily shown in FIGS. 1a and 1b of the accompanying drawings.
Referring to FIGS. 1a and 1b, reference numeral 1 represents a stitching needle supported for movement in a direction up and down perpendicular to a fabric guide bench 2 in a manner well known to those skilled in the art. Reference numerals 3 and 4 represent respective guide plates mounted on a feed plate 5, the spacing l1 between said guide plates 3 and 4 being adjustable. The feed late 5 is mounted on the fabric guide bench 2 and is adapted to be driven by a suitable drive mechanism (not shown) so as to move in sliding contact with the fabric guide bench 2 reciprocatingly and cyclically in a direction shown by the arrow-headed line a-b and also in a direction shown by the arrow-heated line c-d. A sew-through button 6 having two pairs of sew-through holes is shown as already fastened to, that is, sewed on, a piece of fabric 8 through respective looped threads 7.
The guide plates 3 and 4 have respective cut grooves 3A and 4A defined therein so as to extend downwardly and inwardly from an upper edge thereof for receiving therein the looped threads 7 with the guide plates 3 and 4 held in contact with the piece of fabric 8 and the sew-through button 6, respectively, to keep the piece of fabric 8 and the sew-through button 6 spaced apart from each other while the looped threads 7 can extend generally horizontally, that is, in a direction generally parallel to the fabric guide bench 2 in readiness for the bundling operation to be subsequently performed. It is to be noted that the piece of fabric 8 is shown as folded to allow the fastened sew-through button 6 to protrude with the looped threads 7 extending in a direction generally parallel to the fabric guide bench 2. Thus, the guide plates 3 and 4 cooperate with each other as a combined button holder and spacer.
After the looped threads 7 fastening the sew-through button 6 to the piece of fabric 8 has been set in a predetermined bundling position as described above with reference to FIGS. 1a and 1b, the sewing machine is electrically powered to drive the stitching needle reciprocatingly up and down and, at the same time, to drive the feed plate 5 reciprocatingly and cyclically in the directions a-b and c-d so that, as shown by points A to N in FIG. 2, the feed plate 5 can be stepwise moved for each stitch to turn a bundling thread 9 around the looped threads 7 to form a spinned cluster of thread to bundle the turns of thread of the looped threads 7 together.
According to the prior art, at the start of the bundling operation performed in the manner as hereinabove described, the first stitch is initiated from a point shown by 0 in FIG. 2 which is located adjacent the root of the looped thread 7, that is, adjacent the piece of fabric 8.
Referring again to FIGS. 1a and 1b. and in the prior art sewing machine shown therein, the presence of the guide plate 4 tends to restrict the first stitch of bundling operation to be initiated from the point 0 as shown in FIG. 2, that is, adjacent the root of the looped thread 7. Because of this, an end portion of the bundling thread 9 corresponding to the first stitch cannot be firmly retained in position and is apt to be loosened and, therefore, even though that end portion of the bundling thread 9 has once been wound around the looped thread 7, that end portion of the bundling thread 9 is loosened to displace out of the way as the stitching needle is moved upwards. Once this occurs, a looper in the sewing machine tends to fail to catch the bundling thread 9 during the bundling operation and, as a result, a further bundling operation subsequent to the first stitch will no longer be performed and, if not impossible, the bundling thread 9 once turned around the looped thread tends to be loosened.
Another example of the prior art sewing machine capable of performing the bundling operation is fragmentarily shown in FIG. 3. Referring now to FIG. 3, reference numeral represents a stitching needle supported for movement reciprocatingly up and down along a line shown by the phantom line in a direction substantially perpendicular to a needle plate 13. The needle plate 13 is, as best shown in FIG. 4, provided with a protruding land 13b having defined therein a generally elongated slot 13a for the passage of the stitching needle 1 therethrough during the up and down movement thereof. Reference numeral 14 represents a button holder for elastically releasably holding a sew-through button 6 in engagement with opposite peripheral edge portions of the sew-through button 6 from opposite sides. Reference numeral 19 represents a fabric holder for supporting a piece of fabric 8, on which the sew-through button 6 has already been sewed through the looped thread 7, in such a manner that the piece of fabric 8 is folded therearound with the looped thread 7 extending generally horizontally, that is, in a direction generally perpendicular to the direction of movement of the stitching needle 1. It is to be noted that the piece of fabric 8 retained on the fabric holder 19 is fixedly positioned on the needle plate 13 and the fabric guide bench (not shown in FIG. 3). With the piece of fabric 8 and the sew-through button 6 supported fixedly by the fabric holder 19 and the button holder 14, respectively, the looped thread 7 can extend generally horizontally, that is, in a direction generally perpendicular to the direction of movement of the stitching needle 1, while traversing over the slot 13a in the needle plate 13.
When it comes to the bundling operation performed by the prior art sewing machine of the construction shown in FIGS. 3 and 4, where the minimum distance between the piece of fabric 8 on the fabric holder 19 and the sew-through button 6, that is, the width over which the spinned cluster of thread is to be formed as a result of the bundling operation, is relatively great, the bundling thread 9 can be turned around the looped thread 7 while substantially uniformly distributed over the width l when the button holder 14 and the fabric holder 19 are reciprocatingly and cyclically driven in a horizontal plane in two respective directions perpendicular to each other.
However, where the width is relatively small, the range over which the movement in one of the directions, that is, frontwardly and rearwardly, is effected is required to be reduced considerably or the movement in the other of the directions, that is, leftwards and rightwards, must be disabled, so that the bundling thread can be turned several times at the same position so as to form a generally radially outwardly bulged cluster of thread around the looped thread. In such case, since the resultant spinned cluster 9a of thread wound around the looped thread 7 represents a generally radially outwardly bulged shape at a portion of the looped thread intermediate between the sew-through button 6 and the piece of fabric 8, the sew-through button can be fastened to the piece of fabric in an aesthetically unpleasant manner but also a relatively increased number of stitches is required. Moreover, the sew-through button cannot be firmly fastened to the piece of fabric even with the increased number of stitches.